Though the scrollbar doesn't appear, it is possible to scroll the text using the usual touch gestures. Not showing the scrollbar ahead of touch interactions is fairly a widespread approach on mobile platforms.
Running Android 10 on Motorola phone in PApps player/app and no scrollbars are displayed when text overflows.
Even if @miglisic's opinion that not showing scrollbars on touch platforms is widespread, that just means a stupid design is widespread. I.e. when a text input control contains blank lines and they fall at the bottom edge of the control, there is no visual clue to the user that they are not seeing the full text value.
I get it if the underlying render engine in the mobile device can't be forced to show a scrollbar, but if that is NOT the case, please fix text controls to display scrollbars when their contents are overflowing the display area on all devices (or make an optional setting for the text controls), PApps Product Team.